To obtain a screen classifier which can screen crushed stones or the like in large quantities at high speeds.

An upper side moving part 4' of an endless turning screen net 4 is moved between both side plates 3, 3 supported on a machine base 1 through a spring 2, while a plurality of rollers 5 for supporting the underside of the moving part 4' are bridged between the plates 3, 3. An eccentrically/ turning vibrator 6 is provided near one of the opposite ends of the plate 3. In a discharge hopper 7, minus mesh materials of the moving part 4' can be discharged sidewards from a portion between the upper and lower moving parts 4', while oversize materials can be discharged from the part 4' on one of the ends of the plate 3, and raw materials are supplied onto the other end of the part 4' on the other end of the part 3. The vibrator 6 is disposed in such a manner that an eccentric bearing 9 of an eccentrically/turning axis 8 of the vibrator 6 is provided on the spring 2 provided on the base 1 on each side of the end of the plates 3, and a center bearing 10 of the axis 8 is provided for the plate 3, while a drive device 11 is provided to rotate the axis 8 about its eccentric axis (c) upwards from the other end and further from above to one end thereof.